The primary goal of this proposal is to develop a novel fragmentation technique based on interaction of peptide ions with radical beam. We plan to demonstrate that this technique will produce different type of fragment ions compared to those obtained in collision-induced dissociation. It will also overcome problems associated with collision-induced dissociation, e.g. preferential fragmentation and facile losses of labile groups involved in many important posttranslational modifications. Combining both fragmentation techniques in one high performance QqTOF mass spectrometer will substantially increase the value of these instruments for high throughput proteomics applications. PUBLIC HEALTH RELEVANCE: Proteomics studies biological processes by the systematic analysis of the proteins expressed in a cell or tissue. It plays an important role in modern life sciences, drug discovery, and clinical applications. We propose a new high throughput technology for increasing the efficiency of protein identification and structure elucidation using tandem mass spectrometry.